As part of an underground system they electrically isolate pipelines from metallic casings. As well, the CSF/CSK products can be used to prevent the corrosion of above ground flanges and mechanical couplers. The sleeve consists of an irradiation, crosslinked, heat-shrinkable polyolefin backing, coated with an aggressive adhesive that effectively bonds to commonly used pipeline coatings including polyethylene, epoxy, tapes and coal tar enamel. Materials used in these products provide high electrical resistivity, resistance to corrosive environments, low water absorption and low moisture permeability. This combination ensures a permanent seal that is resistant to pipe deflection, vibration, soil stress, corrosive gases, and thermodynamic effects resulting from the expansion and contraction of carrier and casing pipes, flanges and mechanical couplers.